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Determination and Rietveld refinement of the crystal structure of Li0.50Ni0.25TiO(PO4) from powder X-ray and neutron diffraction

Published online by Cambridge University Press:  06 March 2012

B. Manoun
Affiliation:
LCMS, UFR Science des Matériaux Solides, Faculté des Sciences Ben M’Sik (UH2M), Avenue Idriss El Harti, BP 7955, Casablanca, Morocco
A. El Jazouli*
Affiliation:
LCMS, UFR Science des Matériaux Solides, Faculté des Sciences Ben M’Sik (UH2M), Avenue Idriss El Harti, BP 7955, Casablanca, Morocco
P. Gravereau
Affiliation:
Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB-CNRS), 87, Av. du Dr A. Schweitzer-33608 Pessac Cedex, France
J. P. Chaminade
Affiliation:
Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB-CNRS), 87, Av. du Dr A. Schweitzer-33608 Pessac Cedex, France
F. Bouree
Affiliation:
Laboratoire Léon Brillouin (CEA-CNRS), CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
*
a)Author to whom correspondence should be addressed; electronic mail: jazouli@mailcity.com

Abstract

The structure of the oxyphosphate Li0.50Ni0.25TiO(PO4) has been determined from conventional X-ray and neutron powder diffraction data. The parameters of the monoclinic cell (space group P21/c, Z=4), obtained from X-ray results, are: a=6.3954(6) Å, b=7.2599(6) Å, c=7.3700(5) Å, and β=90.266(6)°; those resulting from neutron study are: a=6.3906(7) Å, b=7.2568(7) Å, c=7.3673(9) Å, and β=90.234(7)°. Refinement by the Rietveld method using whole profile, leads to satisfactory reliability factors: cRwp=0.128, cRp=0.100, and RB=0.038 for X-ray and cRwp=0.110, cRp=0.120, and RB=0.060 for neutrons. The structure of Li0.50Ni0.25TiO(PO4) can be described as a TiOPO4 framework constituted by chains of tilted corner-sharing TiO6 octahedra running parallel to the c axis and cross linked by phosphate tetrahedra. In this framework, there are octahedral cavities occupied by Li and Ni atoms: Li occupies the totality of the 2a sites and Ni occupies statistically half of the 2b sites. Ti atoms are displaced from the center of octahedra units in alternating long (2.242 Å) and short (1.711 Å) Ti–O bonds along chains.

Type
Technical Articles
Copyright
Copyright © Cambridge University Press 2002

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References

Bérar, J.-F.and Lelann, P. (1991). “E.S.D.’s and estimate probable errors obtained in Rietveld refinements with local corrections,” J. Appl. Crystallogr. JACGAR 24, 15. acr, JACGAR CrossRefGoogle Scholar
Boultif, A.and Louër, D. (1991). “Indexing of powder diffraction patterns for low symmetry lattices by the successive dichotomy method,” J. Appl. Crystallogr. JACGAR 24, 987993. acr, JACGAR CrossRefGoogle Scholar
Brese, N. E.and O’Keeffe, M. (1991). “Bond-valence parameters for solids,” Acta Crystallogr., Sect. B: Struct. Sci. ASBSDK B47, 192197. acl, ASBSDK CrossRefGoogle Scholar
Brown, I. D.and Altermatt, D. (1985). “Bond-valence parameters for solids,” Acta Crystallogr., Sect. B: Struct. Sci. ASBSDK B41, 244247. acl, ASBSDK CrossRefGoogle Scholar
Caglioti, G., Paoletti, A., and Ricci, F. P. (1958). “Choice of collimators for a crystal spectrometer for neutron diffraction,” Nucl. Instrum. NUINAO 3, 223228. nun, NUINAO CrossRefGoogle Scholar
El Jazouli, A., Krimi, S., Manoun, B., Chaminade, J. P., Gravereau, P., and de Waal, D. (1998). “Preparation and structural characterisation of two new titanium phosphates Na4Ca0.5Ti(PO4)3 and Ni0.5TiOPO4,Ann. Chim. Sc. Mat. ZZZZZZ 23, 710.CrossRefGoogle Scholar
Gravereau, P., Chaminade, J. P., Manoun, B., Krimi, S., and El Jazouli, A. (1999). “Ab initio determination and Rietveld refinement of the crystal structure of Ni0.50TiO(PO4),Powder Diffr. PODIE2 14, 1015. pdj, PODIE2 CrossRefGoogle Scholar
Nagornyi, P. G., Kapshuk, A. A., Stus’, N. V., Slobodyanik, N. S., and Chernega, A. N. (1991). “Preparation and structure of the lithium titanium double phosphate LiTiOPO4,Russ. J. Inorg. Chem. RJICAQ 36, 15511552. rji, RJICAQ Google Scholar
Robertson, A., Fletcher, J. G., Skakle, J. M. S., and West, A. R. (1994). “Synthesis of LiTiPO5 and LiTiAsO5 with the α-Fe2PO5 structure,” J. Solid State Chem. JSSCBI 109, 5359. jss, JSSCBI CrossRefGoogle Scholar
Rodriguez-Carvajal, J. (1993). “Recent advances in magnetic structure determination by neutron powder diffraction,” Physica B PHYBE3 192, 5569. phb, PHYBE3 CrossRefGoogle Scholar
Shannon, R. D. (1976). “Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides,” Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. ACACBN A32, 751767. aca, ACACBN CrossRefGoogle Scholar